Field of the Invention
This invention relates generally to systems for telephonic communications with audio message storage and retrieval and, more particularly, to telephonic communications involving repertory or abbreviated call signal generation and abbreviated dialing.
Description of the Related Art
Voice-dialing systems enable telephone users to speak the name of an individual or destination into the microphone of a telephone handset to initiate a telephone call. Voice-dialing thus allows a connection to be made directly, and avoids the necessity of dialing telephone numbers or looking up names to locate corresponding telephone numbers and then dialing the numbers.
Examples of experimental voice-dialing systems appear in L. R. Rabiner, J. G. Wilpon, and A. E. Rosenberg, "A voice-controlled, repertory-dialer system," Bell System Technical Journal, Vol. 59, No. 7 (September, 1980), and U.S. Pat. No. 4,348,550 to Pirz et al. Longstanding problems with such systems, however, limited their performance in terms of both accuracy and computational speed.
Recent advances in automatic speech recognition have improved performance dramatically, particularly for systems that are not trained to a particular speaker, which have, until recently, performed much worse than systems trained to particular speakers. In addition, the increasing computational and memory capacity and decreasing cost of computing hardware have significantly improved the commercial viability for the simpler applications of speech recognition such as voice-dialing.
Limitations on the performance of voice-dialing systems, however, still significantly reduce their commercial applicability. Such systems frequently make mistakes, the rate of error increasing with increasing vocabulary size, changes in environment, unusual accents, and the use of foreign or unusual names that might be difficult to pronounce. This limited accuracy restricts the possible range of applications for conventional systems to those with limited vocabularies, tightly controlled environments, and small user populations. There are also restrictions placed on the hardware platforms on which the systems can run.
It is therefore desirable to seek techniques that will improve the accuracy, speed, and ease of use of voice-dialing systems. A number of alternative techniques have been used in the past. One approach uses an interactive scheme in which the user is asked to verify the name before dialing (e.g., "Did you say Amanda Graham?"), and presenting a different name if the user says "No." See, for example, U.S. Pat. No. 5,222,121 to Shimada, and U.S. Pat. No. 5,301,227 to Kamei et al.